Acrylamide cancer link confirmed

A study has for the first time confirmed the proposed link between dietery intake of acrylamide and cancer - five years after the suspected carcinogen was detected in cooked food.

Those who ingest more acrylamide via their diet are twice as likely to develop womb or ovarian cancer, a Dutch study involving 62,000 women over 11 years has concluded.

In 2002, Swedish researchers provoked worldwide concern when they discovered people were taking in acrylamide through their diet - including such common foods as crisps, potato chips, coffee, biscuits, and bread. The chemical was known to cause tumours in rats, is a neurotoxin, and seemed likely to be a human carcinogen too. Later research showed that whenever food is fried, roasted or grilled to turn a tasty golden brown, acrylamide is also formed, via the Maillard reaction of amino acids such as asparagine with reducing sugars above 120°C.

These were worrying discoveries, but large-scale epidemiological studies on men and women in Sweden and the US had found no link between increasing dietary acrylamide intake and the risk of various cancers including breast, colorectal, bladder and renal cancer.

Now researchers led by Janneke Hogervorst, at Maastricht University, have investigated links with rarer cancers of the womb and ovaries. Each disease affects around 60 per 100,000 post-menopausal women in the UK every year.

The team used a Netherlands study on diet and cancer, in which 120,000 people, and more than 62,000 women, aged 55-70 years, were asked details about their diet. The Dutch researchers used this data to estimate acrylamide intake from foods, and followed up the participants through cancer registries. After 11 years, women who had eaten around 40g of acrylamide a day were twice as likely to develop womb and ovarian cancer as those who'd eaten around 9g a day. There was no increased risk of breast cancer. The team did not look at the effects of acrylamide on men.

A previous Italian study had found no link between acrylamide and ovarian cancer. But it had asked people with the disease to recall their earlier diet - a method which has greater potential for bias.

Lorelei Mucci, who has conducted many epidemiological acrylamide studies at the Harvard School of Public Health in Boston, US, told Chemistry World that the Dutch study was well designed. The researchers had done their best to control for the effects of other risk factors for cancer such as smoking or a high intake of fatty foods, she noted. Particularly interesting in this study was that Dutch spiced cake - a kind of non-crusty gingerbread - accounted for most of the variation in acrylamide intake. In Swedish and US populations, noted Mucci, coffee and fried potato chips are the main sources of acrylamide. Both Hogervorst and Mucci emphasised that further corroboration of the results are needed from other studies on different populations.

Inside the body, acrylamide metabolises to glycidamide, which forms adducts with haemoglobin and DNA. But the associations with ovarian and womb cancers have led to speculation that acrylamide may also disrupt proteins which maintain hormone balance in the body, said Hogervorst.

European scientists and food manufacturers have already made many efforts to reduce acrylamide production in foods - mainly funded by the European Commission's 4-year strategic acrylamide project, HEATOX, which was completed on 26 November. However, removing it from the diet completely would be nigh on impossible. Other genotoxic compounds, such as furans, are formed when food is cooked. And fatty foods and smoking are far more strongly associated with the risk of common cancers.